Workers in the system receive compensation and benefits "that are consistent" with the quick-service industry, according to the statement.

The National Retail Federation called Thursday's protests a "publicity stunt" in a statement, saying that they're "just further proof that the labor movement is not only facing depleted membership rolls, they have abdicated their role in an honest and rational discussion about the American workforce."

Looking ahead, Brent Giddens, managing partner in the Los Angeles office of employment and labor law firm Carothers DiSante & Freudenberger, said he's skeptical of protesters' chances of success.

"I can't see the federal minimum wage rising to anywhere near $15 an hour," said Giddens, whose firm's clients have included Taco Bell and Jack in the Box. "It would have a devastating effect on the economy and can only have the effect of driving labor out of the country."

However, Giddens said he "would not at all be surprised" to see a minimum wage increase in California, where the lowest legal hourly pay is $8.

"The political climate here is very favorable toward employees and historically always has been," he said. "Nobody can argue that California is not among the most protective of employee rights among all the states."

Amina Hall hopes it stays that way. The high school senior, protesting in South L.A., said she wanted a raise from her current $8-an-hour pay at the store so she could help her jobless mother support her large family while also padding her college tuition fund. The 17-year-old works part-time, mostly as a cashier, but doesn't see a future in the gig.

"It's not something I want to do long-term," said Hall, who dreams of becoming a criminal justice attorney. "I want to make a career for myself."

Twitter: @tiffhsulatimes, @alanasemuels

Hsu reported from Los Angeles and Semuels from New York.